Twelve-Year Risk of Revision After Primary Total Hip Replacement in the U.S. Medicare Population
Bibliographic record
Abstract
BACKGROUND: There is limited population-based literature on rates and risk factors for revision following primary total hip replacement. METHODS: We performed a retrospective cohort study of Medicare beneficiaries who had elective total hip replacement for osteoarthritis between July 1, 1995, and June 30, 1996. Patients were followed with use of Medicare claims through 2008. The primary end point was revision total hip replacement as indicated by hospital discharge codes according to the International Classification of Diseases, Ninth Revision. We used the Kaplan-Meier method to plot the risks of revision and of death over a twelve-year follow-up period. We used Cox proportional hazard regression models to identify preoperative risk factors for revision of primary total hip replacement. We conducted sensitivity analyses to account for competing risks of major comorbid conditions. RESULTS: The risk of revision total hip replacement for patients remaining alive was approximately 2% per year for the first eighteen months and then 1% per year for the remainder of the follow-up period. The absolute risk of death over the twelve-year follow-up period exceeded the risk of revision total hip replacement by a factor of ten (59% vs. 5.7%) in patients older than seventy-five years at the time of primary total hip replacement and by a factor of three (29% vs. 9.4%) in patients sixty-five to seventy-five years old at the time of surgery. In multivariate Cox proportional hazard models, the relative risk of revision was higher in men than in women (hazard ratio [HR], 1.23; 95% confidence interval [95% CI], 1.15, 1.31) and in patients sixty-five to seventy-five years of age at the time of primary total hip replacement than in those over seventy-five years (HR, 1.47; 95% CI, 1.37, 1.58). Patients of surgeons who performed fewer than six total hip replacements annually in the Medicare population had a higher risk of revision than those whose surgeons performed more than twelve per year (HR, 1.21; 95% CI, 1.12, 1.32). CONCLUSIONS: Efforts to reduce the number of revision hip arthroplasties should be targeted at revisions occurring in the first eighteen months following the index arthroplasty, when revision risk is higher, and at younger patients, who are more likely to survive long enough to require revision. .
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.003 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".